Microstructure and Phase Composition of Titanium Coatings Plasma Sprayed with a Shroud

Abstract

Excellent corrosion resistance has made titanium a preferred material for use in industry with harsh environments. Protective titanium coatings combined with cheap bulk materials are expected to enable sufficient corrosion protection and lower the cost. Plasma spray processing of titanium feedstock becomes a challenging topic of research as titanium powder particles have to experience high temperatures in the flight during the thermal spraying process in an open air environment. In this paper, plasma spraying of titanium has been carried out by using a shroud in order to shield molten particles from reacting with surrounding environment. Microstructure analyses on the titanium coatings were performed by using SEM, EDS and XRD. The results show that the shroud attachment is capable of withstanding high plasma temperatures; the as-sprayed shrouded titanium coating exhibits a similar phase composition as the pure titanium powder, and an enhanced microstructure with a lower porosity for the titanium coating plasma-sprayed with a shrouding system is observed.